Mixer for concrete and similar hardenable materials



March 12, 1968 L. J. ESTIS 3,372,910

MIXER FOR CONCRETE AND SIMILAR HARDENABLE MATERIALS Filed Nov. 30, 1966 INVENTOR. Lav/WE f 75776 United States Patent Ofifice 3,372,910 MIXER FOR CONCRETE AND SIMILAR HARDENABLE MATERIALS Lonnie J. Estis, Mobile, Ala., assignor of one-half to Wright Smith, Jr., Mobile, Ala. Filed Nov. 30, 1966, Ser. No. 598,083

2 Claims. (Cl. 259-478) ABSTRACT OF THE DISCLOSURE A stationary generally cylindrical mixing drum for concrete, etc., in which there is a rotatable horizontally extending shaft provided with mixing paddles carried on arms extending normal to the shaft. Loose metallic rings are carried by the shaft and by the arms to eliminate the accumulation of cementitious material thereon.

This invention relates to mixing machines for concrete and similar materials which are hardenable upon setting.

Mixing machines of the general type to which the present invention applies comprise a drum with a circular interior (i.e. cylindrical or frusto-conical in whole or in part) which is disposed horizontally or substantially horizontally and provided with an axially aligned rotatable shaft carrying a plurality of radially extending mixing blades. Depending on the particular type of mixer, the mixing blades may be adapted to feed the mixture from one end of the drum to the other or from the middle of the drum toward both ends.

In the case of cement mixing machines, a mixture of aggregates, Portland cement and water is placed in the drum; and the cement mixture removed therefrom after a suitable period of contact by and with the mixing blades which are carried by, and extend radially of, the rotatable shaft.

Sometimes such cement mixing machines are disposed over a hopper which directly communicates with a concrete block manufacturing machine.

Quite often cement mixing machines of the type described are used over a substantial period of time, such as seven or eight hours, during which the cement and aggregates build up a sort of ball around the rotatable shaft, and to a somewhat lesser extent, the radially extending mixing blade arm as well. This balling around the rotatable shaft and its radially extending mixing b'l'ade arm greatly decreases the efiiciency of the cement mixing machine; and at the end of a run of substantial duration, such as seven or eight hours, is of such size and nature to make its removal diflicult even when heating it with large hammers or sledges.

In the past it has been proposed to provide the rotatable shaft and/or the radially extending mixing blades of a cement mixing machine with instrumentalities which are intended to enhance the mixing action; but so far as I am aware no one has heretofore proposed a truly practicable device for eliminating or reducing the objectionable balling action referred to.

Accordingly, it is among the objects of the present invention to provide an eflicient and practical means for association with a mixer of the class described which will practically eliminate, or vary substantially reduce, the accumulation and setting, or partial setting, of large quantities of the material being mixed on either the rotatable 3,3 72,910 Patented Mar. 12, 1968 shaft or the mixing blade arms and extending radially therefrom.

Another object is the provision of means possessing the characteristics described immediately hereinbefore which is durable in service, yet simple and inexpensive to manufacture, install and replace should the need therefor arise.

Another object is to attain the stated objectives and advantages by utilizing certain instrumentalities, as will appear hereinafter, which may be expediently and inexpensively installed on mixers of existing design.

The foregoing and other objects and advantages will he more fully understood from the following description and annexed drawing wherein like reference numerals designate like parts, and wherein:

FIGURE 1 is a perspective of a more or less conventional cement mixing apparatus which embodies the teachings of the present invention; and

FIGURE 2 is an enlarged schematic detail.

Referring more particularly to FIGURE 1, the numeral 2 generally designates the cylindrical drum of the cement mixing apparatus which is closed at both ends, as shown at 4 and 5.

The end closures 4 and 5 of the cylindrical drum 2 are centrally apertured and provided with bearings 01' trunions 6 and 7 in which there is journaled a suitably driven rotatable shaft 10 which extends axially of said drum.

The rotatable shaft 10 carries a plurality of substantially evenly spaced arms 12 which extend radially or right-angularly therefrom.

Each of these arms 12 is provided adjacent its outer end with a paddle or stirring member 14.

As shown, the drum 2 is provided with suitable inlet and outlet openings, etc.

Pursuant to the teachings of the present invention, the rotatable shaft 10 carries one or more loosely disposed metallic rings 15 on the portions thereof which are between the aforementioned arms 12 (or all sections of the shaft) which extend radially or right-angularly therefrom; and one or more similar loosely disposed metallic rings 16 is carried by each of the said arms 12 and its outwardly disposed paddle or stirring member 14.

As shown, the metallic rings 15 and 16 are of substantial thickness and being loosely mounted are susceptible of vigorous tumbling action with respect to the instrumentalities by which they are carried, i.e. the rotatable shaft 10 and laterally extending arms 12.

The positioning of the loose rings 15 and 16 in the manner described very effectively eliminates or materially reduces the objectionable accumulation of cementitious material on either the rotatable shaft 10 or the arms 12.

While the invention contemplates other means, it has been found very satisfactory to make up the metallic rings 15 and 16 in semi-circular metallic sections; assemble a pair of such sections with the ends thereof in substantial alignment, and the composite ring embracing the element to which it is to be associated; and then welding the ends of said sections to each other.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent is:

'1. Apparatus for mixing cement and similar materials which are hardenable upon setting comprising a substantially horizontally dispose-d drum having a circular inner wall and a closure at each end; a rotatable shaft disposed in and extending axially of said drum; a plurality of arms which are mounted on,

carried by and extending right-angularly of said rotatable shafit; said arms being in substantially spaced relationship with respect to each other in a direction which is longitudinal of said rotatable shaft; a mixing blade carried by each of said arms; said mixing blade being disposed in spaced relationship with respect to the inner end of the arm by which it is carried; and at least one circular metallic ring loosely carried by said rotatable shaft; said metallic ring being of such thickness and diameter that its loose association with said rotatable shaft provides a vigorous tumbling action which is effective in preventing the substantial accumulation of the material being mixed upon any parts of the apparatus with which it comes into contact.

2. The combination of claim 1 together with at least 10 one metallic ring loosely mounted on said arms between its inner end and the inner end of the mixing blade carried thereby; said metallic rings being of such thickness and diameter that their loose association with said arms provides a vigorous tumbling action which is effective in preventing the substantial accumulation of the material being mixed upon any part of the apparatus with which they come into contact.

References Cited UNITED STATES PATENTS FOREIGN PATENTS 471,985 11/1914 France.

26,972 11/1913 Great Britain.

ROOBERT W. JENKINS, Primary Examiner. 

